N-methyl pyrrolidone manufacturing wastewater as the electron donor for denitrification: From bench to pilot scale.

Actual wastewater generated from N-methylpyrrolidone (NMP) manufacture was used as electron donor for tertiary denitrification. The organic components of NMP wastewater were mainly NMP and monomethylamine (CHNH), and their biodegradation released ammonium that was nitrified to nitrate that also had to be denitrified. Bench-scale experiments documented that alternating denitrification and nitrification realized effective total‑nitrogen removal.

The roles of Rhodococcus ruber in denitrification with quinoline as the electron donor.

Denitrification is an important step in domestic wastewater treatment, but providing bioavailable electron donors is an expense. However, some industrial wastewaters contain organic compounds that could be a no-cost or low-cost electron donor, because they otherwise must be treated separately. In this work, quinoline was used as an electron donor to drive denitrification through bioaugmentation with Rhodococcus ruber, which is able to biodegrade quinoline.

Anoxic/oxic treatment without biomass recycle.

The Anoxic/Oxic (A/O) process involves recirculating mixed liquor between its A and O tanks so that nitrate produced in the O tank can be used to for denitrification with influent COD in the A tank. Because biomass is recirculated along with nitrate, A/O operation leads to similar microbial communities in the A and O tanks, which may decrease the rates of denitrification and nitrification in each tank. Here, bench-scale experiments simulated this aspect of the A/O process by exchanging biomass between an anoxic flask and an oxic cylinder at exchange ratios of 0%, 20%, 30%, and 50%.

Selective acceleration of 2-hydroxyl pyridine mono-oxygenation using specially acclimated biomass.

Biodegradation of pyridine starts with two mono-oxygenation reactions, and 2-hydroxyl pyridine (2-HP) accumulates as pyridine is mono-oxygenated in the first reaction. The accumulation of 2-HP inhibits both initial reactions. Therefore, selective acceleration of the second mono-oxygenation reaction should significantly enhance pyridine transformation and mineralization.

Synergy of strains that accelerate biodegradation of pyridine and quinoline.

Three bacterial strains were isolated from activated sludge acclimated to biodegrade pyridine and quinoline simultaneously. The strains were identified as Bacillus tropicus, Bacillus aquimaris, and Rhodococcus ruber. When the isolated bacteria were used for pyridine and quinoline biodegradation in separate or combined modes, R.

How bioaugmentation with Comamonas testosteroni accelerates pyridine mono-oxygenation and mineralization.

Pyridine is a common heterocycle found in industrial wastewaters. Its biodegradation begins with a mono-oxygenation reaction, and bioaugmentation with bacteria able to carry out this mono-oxygenation is one strategy to improve pyridine removal and mineralization. Although bioaugmentation has been used to enhance the biodegradation of recalcitrant organic compounds, the specific role played by the bioaugmented bacteria usually has not been addressed.